The objectives of this proposal are: i) to optimize and validate positron emission tomography (PET) activation techniques as a method of functional brain mapping in single subjects, and 2) to apply these techniques to better understand processes of sensory-motor integration in the human. PET studies will use radioactively labeled water as a means of measuring regional changes in blood flow in response to behavioral tasks. The methodologic aspects of this proposal will focus on improvements in signal-to-noise ratios by using better imaging protocols, development of more accurate statistical models for analyzing data from individual subjects, and independent validation of PET findings by comparing the results with those obtained using other methods of functional evaluation. The objective of these methodologic investigations is to develop functional brain imaging as a valid, rigorous tool for the study of normal and abnormal brain physiology in individual subjects. The objective of the neuroscientific component of the proposal is to use this tool to better understand sensory-motor integration in the human. Initial studies will map sensory-motor processes in normal subjects as a function of the sensory input modality and the motor output modality. Participation of the parietal lobe in sensory-motor tasks will be of particular interest, but the demonstration of one or more widespread cortical networks involved in sensory-motor integration is anticipated. Further studies will examine the -lateralization of sensory-motor processing in normal subjects to look for evidence of hemispheric asymmetries. During the final two years of the proposal, patients with sensory-motor deficits and/or with lesions in brain structures normally involved in sensory-motor integration will be studied. Multimodal integration of clinical observations, functional imaging studies, anatomic imaging studies, and electrophysiologic measurements will be utilized in normal subjects and in patients to further clarify the relationship between brain structure and function.